1. Field of Invention
The present invention pertains to the field of imaging. More particularly, this invention is directed toward a solid fiduciary marker that can be molded into a desired shape and is detectable in a plurality of imaging modalities including, but not limited to, Nuclear Medicine such as Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), including planar modalities; Radiology such as X-Ray Computed Tomography (CT), also including planar modalities; Magnetic Resonance Imaging (MRI); and optical imaging.
2. Description of the Related Art
Image registration has been a topic with much interest. It has many applications including, but not limited to, radiotherapy, functional imaging, and molecular imaging. Having fixed fiducial markers not only permits rigid, inelastic, registration of the images, but also provides true mutual information markers that can guide elastic transformation between devices, between subjects and even to generic topologies such as Tailerac maps.
The new markers have a practical lifetime of over one (1) year. Accordingly, they may be affixed to restraint devices and beds for use in multiple studies. Further, because the doping concentration is controlled and because of their small size, the markers may be embedded in molded fixation devices used with specific subjects or patients. Thus, the markers may be used in radiotherapy protocols which require tight control of the treatment beam. After therapy has been completed, the markers may be salvaged or discarded. The same molded fixation device may be used when longitudinal PET, SPECT, CT and/or MRI studies are to be done on the same subject.
Current technology relies on non-reusable liquid filled markers to achieve registration across various imaging modes. In order to obtain nuclear medicine images with current technology, the marker must be injected with a liquid containing the appropriate nuclide and this represents a contamination hazard. This methodology limits the size and shape of the marker and presents problems in determining the precise marker location. This methodology also limits the amount of time between studies due to its disposable single use construction and short-lived isotopes.
A sample of a current commercial marker is that manufactured by IZI Medical Products. In order to achieve registration for nuclear imaging the product must be injected with a short-lived liquid based nuclide.